The overall objective of the chemical sensitive field-effect transducer (CHEMFET) program (NIGMS Grant #GM 22952) is the development of biomedical sensors based upon integrated circuit technology. The primary goals of this program are to prove feasibility of this new technology and to develop single ion sensitive field effect transducers (ISFET) and reducible gas sensitive field effect transducers (GASFET). Secondary goals, as originally defined, included the development of CHEMFETs to detect enzymatic reactions (ENFET) and immunochemical reactions (IMFET). The ENFET and IMFET device development efforts have been restricted due to the amount of funding available for these research areas.